The short answer is No. Contributing Editor Josh Cosford explains why:
I’ve never seen copper washers used in hydraulics. Even though it’s a little bit malleable, it’s not soft enough to allow positive seal between too hard surfaces. There are some companies that make some seals that can go on a JIC so that it has a soft seal between two surfaces. If it’s a temporary thing, the chances of getting a copper washer to the exact shape and dimensions of the fittings that you’re trying to seal up again is going to be hard to come by.
Instead of going out to look for washers, you’d be better off going out look for somebody that can redo your hose or get some new fittings for you. But, I wouldn’t recommend that either. It just sounds like a disaster for leakage. The pressure is too high. If there’s any imperfections in the surfaces between the copper washer and the metal of the fitting or the tubing or whatnot, at 3,000 psi, it’ll find its way through there. The copper washer is not going to stop it.
Cnote says
I literally just tried this. somehow this guy managed to get a deep gouge on the taper of his bucket cylinder fitting. (Top to bottom. It was pretty heartbreaking after rebuilding the cylinder.
1st i lightly sanded the gouge w 300 g until it was relatively smooth and uniform. Obviously not uniform enough after removing matierial. So it still leaked
Living on a mountain there arent many options..so the copper washer popped in my head.! Like any metal coppers are not all the same!
First i drilled a hole so the washer sat perfectly on top of the taper, then i slowly tightened the fitting which shaped the copper washer absolutely perfectly. I took it off to inspect the shape, and then tightened it down fully. Erika! It absolutely worked and is still working flawlessly. Is is right nope, did it work? yep. You bet your azz.
I imagine over time the fluid could waterjet through somehow. But that day isnt today or tomorrow.
This 100% worked on this mid size ag tractor .